Monthly Archives: October 2013

This jukebox is a beauty, with a wonderful patina that I don’t see very often because it still had its original plastics and the original chrome has worn off most of the metal. Most jukeboxes of this vintage have had their plastics replaced and their metal re-chromed. My initial instinct was to replace the plastics and make it look like new. But the old plastics with their muted transparency really grew on me. Besides, it doesn’t look like anyone is still making reproduction plastics for this model.

Wurlitzer 850 Jukebox at night (Click for larger)

And because the German Wurlitzer company recently made reproductions, the patina sets this one apart.

Daytime view

On to the repairs…

There were a lot of small problems with the mechanism because it was gummed up. It looked like the mech was cleaned sometime in the 1990’s so there wasn’t a ton of old grease. It just needed some fresh lube. It also needed some adjustments as the turntable wasn’t lifting high enough and it wasn’t tripping correctly at the end of the records.

The amp didn’t sound good, but it turned out the needle wasn’t seated into the cartridge correctly.

Some of the wiring in the switch junction box wasn’t looking safe, so I rewired it. Some of it previously had been bypassed.

The left bubble tube was broken due to a blow to the lower grill castings of the jukebox, probably during moving. Unfortunately it broke the threaded anchor points for the screws in the castings. I removed the grill castings and used some metal epoxy to attach some new standoffs and reinforce one that was remaining.

Rear of front grill casting with new threaded standoff attached.

The speaker bushings were replaced with new ones, as the old rubber bushings were brittle and broken.

Everything was looking, sounding and working pretty well when it was done. The repairs were performed over the course of a couple of months.

After checking the mechanical operation of the ramp and running switch tests, I concluded (or guessed) that the microswitches on the ramp and ball trough were acting intermittently.

Sometimes when a machine acts weird like this, you have to think about what the firmware is attempting to do. In the case of the ramp, it tries to lower the ramp because it hasn’t sensed that it has been lowered. So it would keep trying 4 or 5 times before giving up.

The reason the computer was delivering two balls to the shooter lane is that it wasn’t sensing the first ball had actually made it to the shooter lane, so it would try again.

Both of these problems weren’t consistent which led me to the intermittent switch idea. The microswitches were probably dirty and worn inside. Unfortunately, since they are totally enclosed they can’t be easily cleaned. Sometimes I can flush the switches out with contact cleaner, and get them working again. In this case, it worked!

This machine sat neglected prior to the current owner purchasing it. Although the NiCad battery looked ok and looked like it had been replaced relatively recently, there was a lot of corrosion on the CPU board. It was even affecting the RAM sockets, where I could see blue-green corrosion in the socket holes. During the boot process, the LED would only flash a couple of times, indicating a RAM failure.

Normally I would try to fix something like this. In this case, since there was an aftermarket CPU board available, I recommended the owner purchase the new board. With the old board, I could fix one thing, only to learn something else was damaged by the corrosion. It turned out I was correct, except the corrosion had spread to the sound board, which sits right below the battery. It had damaged the sockets there as well.

I was able to get the sound board working with some cleaning.

The rubber rings and burned out bulbs were replaced, and the playfield cleaned as well.

It seems like every Gottlieb – Premier pinball machine I work on has over-fused flippers. The fuse should be 2.5 amps and in this machine there were 5 amp fuses installed. When the flipper link broke, it caused the flipper arm to not engage the End-Of-Stroke switch, which caused the coil to melt. Had the correct fuse been installed, the coil would have been saved.

I replaced the coil, the fuse and the broken link and everything is fine with the flipper.

The other problem, and I’ve seen this on a Monte Carlo pinball machine (which is the same vintage) is that the switches on the center spinner don’t work. In this case, the spinner wasn’t spinning very fast either. I cleaned and oiled the wiper contacts and the gears. I checked every hole in the spinner and verified that each switch was working.

Reviews

"Randy is a true professional with amazing knowledge of electrical wiring, programming, boards and mechanical workings. He has always arrived promptly with all the tools and parts needed to efficiently complete the jobs. Randy has worked on my three Williams machines (Taxi, T2, and Funhouse) and based on his previous work, I am confident he could solve any future issue." --Greg M., Louisville, CO

"Randy was there an hour and found the problem and also a couple other potential issues. He was very professional and knowledgeable and I feel he has the ability to troubleshoot anything pinball or anything electronic for that matter." --Craig H., Broomfield, CO

"Randy just left here and after over 20 years I now have a jukebox that works."--Jeff, Aurora, CO.

"Randy is always very professional and extremely knowledgeable about the work that needs to be done. He is the best out there that can be found for pinball and juke box repairs."--Larry, Sidney, NE.